{"title":"Nitrogen Dioxide (NO2) Detectors","description":"\u003c!-- gas-type subcollection: nitrogen-dioxide-detectors | smart tag = no2-detector --\u003e\n\n\u003ch2\u003eWhich nitrogen dioxide (NO2) detector should you buy in 2026?\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eShort answer:\u003c\/strong\u003e For nitrogen dioxide, use a dedicated NO2 monitor such as the \u003ca href=\"\/products\/smart-sensor-no2-gas-detector\" title=\"Smart Sensor NO2 Detector\"\u003eSmart Sensor NO2 Detector\u003c\/a\u003e (0-20 ppm) — for diesel exhaust, welding fume and firing ranges, where NO2 is the toxic hazard a 4-gas monitor doesn’t cover.\u003c\/p\u003e\n\n\u003cp\u003eNitrogen dioxide (NO2) is a toxic, reddish-brown gas produced by combustion — diesel engines, welding, and indoor firing ranges are the main sources. It is harmful at low concentrations and a hazard outside the standard four-gas (O2\/LEL\/CO\/H2S) set, so it needs a dedicated NO2 instrument.\u003c\/p\u003e\n\n\u003cp\u003eThis is a gas-type collection under the \u003ca href=\"\/collections\/gas-detectors\" title=\"Gas Detectors\"\u003eGas Detectors\u003c\/a\u003e hub. Match the gas to the right form factor: \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"Portable Gas Detectors\"\u003ePortable Gas Detectors\u003c\/a\u003e for carried checks, \u003ca href=\"\/collections\/personal-gas-detectors\" title=\"Personal \u0026amp; Wearable Gas Detectors\"\u003ePersonal \u0026amp; Wearable Gas Detectors\u003c\/a\u003e for single-worker exposure, \u003ca href=\"\/collections\/fixed-gas-detection-systems\" title=\"Fixed Gas Detection Systems\"\u003eFixed Gas Detection Systems\u003c\/a\u003e for continuous plant monitoring, \u003ca href=\"\/collections\/area-gas-monitors\" title=\"Area \u0026amp; Transportable Gas Monitors\"\u003eArea \u0026amp; Transportable Gas Monitors\u003c\/a\u003e for job-site zones, and \u003ca href=\"\/collections\/gas-leak-detectors\" title=\"Gas Leak Detectors\"\u003eGas Leak Detectors\u003c\/a\u003e to pinpoint a leak source.\u003c\/p\u003e\n\n\u003ch2\u003eDetectors in this collection\u003c\/h2\u003e\n\n\u003cp\u003eThis collection gathers NO2 instruments. The \u003ca href=\"\/products\/smart-sensor-no2-gas-detector\" title=\"Smart Sensor NO2 Detector\"\u003eSmart Sensor NO2 Detector\u003c\/a\u003e is a rechargeable handheld reading 0-20 ppm. For the four atmospheric gases alongside NO2, pair it with a unit from \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"Portable Gas Detectors\"\u003ePortable Gas Detectors\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003cblockquote style=\"background:#1a1a1a;border-left:4px solid #ff9800;padding:14px 18px;margin:18px 0;color:#f5e6d3;\"\u003e\n\u003cstrong style=\"color:#ffb74d;\"\u003eEditor’s pick — a low-range handheld NO2 monitor\u003c\/strong\u003e\u003cbr\u003eThe \u003ca href=\"\/products\/smart-sensor-no2-gas-detector\" title=\"Smart Sensor NO2 Detector\"\u003eSmart Sensor NO2 Detector\u003c\/a\u003e covers diesel-exhaust and welding NO2 with a low 0-20 ppm range and triple alarms at an accessible price. \u003cspan style=\"display:block;margin-top:6px;font-size:0.82em;color:#bdae9d;\"\u003eAs an Amazon Associate, WC Safety earns from qualifying purchases.\u003c\/span\u003e\u003cp style=\"margin-top:12px;\"\u003e\u003ca href=\"https:\/\/www.amazon.com\/s?k=nitrogen+dioxide+no2+detector\u0026amp;tag=wcsafety04-20\" rel=\"sponsored nofollow noopener\" target=\"_blank\" style=\"display:inline-block;background:#FFD814;color:#0F1111;padding:12px 22px;text-decoration:none;font-weight:bold;border-radius:4px;border:1px solid #FCD200;\"\u003eCHECK PRICES ON AMAZON →\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/blockquote\u003e\n\n\u003ch2\u003eHow to choose a nitrogen dioxide detector\u003c\/h2\u003e\n\n\u003ch3\u003eLow range matters\u003c\/h3\u003e\u003cp\u003eNO2 is toxic at low ppm, so choose a low, high-resolution range and set low alarm points.\u003c\/p\u003e\u003ch3\u003eKnow the sources\u003c\/h3\u003e\u003cp\u003eNO2 comes from combustion — diesel exhaust, welding and firing ranges. Monitor where engines run or metal is cut indoors.\u003c\/p\u003e\u003ch3\u003ePlacement\u003c\/h3\u003e\u003cp\u003eNitrogen dioxide is heavier than air, so it collects in low and enclosed areas — place detectors accordingly.\u003c\/p\u003e\n\n\u003ch2\u003eNitrogen Dioxide (NO2) hazard, exposure limits \u0026amp; placement\u003c\/h2\u003e\n\n\u003cp\u003eThe OSHA Permissible Exposure Limit for nitrogen dioxide is a ceiling of about 5 ppm; ACGIH lists a lower TWA. Nitrogen dioxide is heavier than air, so it collects in low and enclosed areas — place detectors accordingly, and it concentrates near diesel and welding sources. Set low alarm points and confirm current limits with \u003ca href=\"https:\/\/www.osha.gov\/annotated-pels\" rel=\"noopener\" target=\"_blank\" style=\"color:#4fc3f7;\"\u003eOSHA's annotated PEL tables\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003ch2 id=\"faq\"\u003eFrequently asked questions\u003c\/h2\u003e\n\u003ch3\u003eWhat detects nitrogen dioxide?\u003c\/h3\u003e\u003cp\u003eA dedicated NO2 detector with an electrochemical sensor — a standard 4-gas monitor does not cover NO2.\u003c\/p\u003e\n\u003ch3\u003eWhere is NO2 detection needed?\u003c\/h3\u003e\u003cp\u003eDiesel-exhaust areas (garages, depots, mining), welding and metal fabrication, indoor firing ranges, and combustion\/boiler areas.\u003c\/p\u003e\n\u003ch3\u003eWhat is the OSHA limit for NO2?\u003c\/h3\u003e\u003cp\u003eA ceiling of about 5 ppm per the \u003ca href=\"https:\/\/www.osha.gov\/annotated-pels\" rel=\"noopener\" target=\"_blank\" style=\"color:#4fc3f7;\"\u003eOSHA PEL\u003c\/a\u003e; ACGIH lists a lower TWA. NO2 is toxic at low levels.\u003c\/p\u003e\n\u003ch3\u003eIs NO2 heavier than air?\u003c\/h3\u003e\u003cp\u003eYes — nitrogen dioxide is heavier than air and concentrates near combustion sources like diesel engines and welding.\u003c\/p\u003e\n\u003ch3\u003eIs NO2 the same as nitric oxide (NO)?\u003c\/h3\u003e\u003cp\u003eNo — they are different nitrogen oxides. NO2 (nitrogen dioxide) is the more acutely toxic and the one usually monitored for exposure.\u003c\/p\u003e\n\u003ch3\u003eDo NO2 sensors need calibration?\u003c\/h3\u003e\u003cp\u003eYes — verify response against NO2 calibration gas periodically and replace the sensor per the manufacturer's guidance.\u003c\/p\u003e\n\u003ch3\u003eCan I use it for confined-space entry?\u003c\/h3\u003e\u003cp\u003eNO2 is one hazard; entry also needs O2, combustible and toxic testing with a \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"portable 4-gas instrument\"\u003eportable 4-gas instrument\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003ePortable or fixed NO2 detection?\u003c\/h3\u003e\u003cp\u003eHandheld units cover surveys and exposure; fixed NO2 detection exists for enclosed diesel and combustion areas. See \u003ca href=\"\/collections\/fixed-gas-detection-systems\" title=\"Fixed Gas Detection Systems\"\u003eFixed Gas Detection Systems\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eIs NO2 a diesel-exhaust marker?\u003c\/h3\u003e\u003cp\u003eYes — NO2 is a key component of diesel exhaust, so NO2 monitoring is common in garages, depots and enclosed diesel-equipment areas.\u003c\/p\u003e\n\u003ch3\u003eHow dangerous is NO2?\u003c\/h3\u003e\u003cp\u003eNitrogen dioxide irritates and damages the respiratory tract even at low concentrations, which is why the OSHA ceiling is around 5 ppm.\u003c\/p\u003e\n\n\u003cdiv style=\"background:#1a2733;border:1px dashed #4fc3f7;padding:16px 20px;margin:30px 0 18px 0;color:#cfd8dc;font-size:0.92em;\"\u003e\n\u003cstrong style=\"color:#4fc3f7;\"\u003eWhy trust this nitrogen dioxide detector collection?\u003c\/strong\u003e WC Safety is an independent industrial safety-equipment retailer. This collection is curated on detection principle, gas coverage and certification, grounded in published OSHA standards and manufacturer data — not paid placement. Disclosed: we earn Amazon affiliate commissions on outbound links; that does not influence what we recommend.\u003c\/div\u003e\n\u003cdiv style=\"background:#1a2733;border-left:4px solid #4fc3f7;padding:18px 22px;margin:18px 0;color:#cfd8dc;font-size:0.92em;\"\u003e\n\u003cstrong style=\"color:#4fc3f7;\"\u003eCurated by Steven Eaton, WC Safety Editorial\u003c\/strong\u003e — Industrial safety-equipment desk · atmospheric monitoring and chemical-specific gas detection.\u003cbr\u003e\n\u003cstrong\u003eLast reviewed:\u003c\/strong\u003e \u003ctime datetime=\"2026-06-22\"\u003eJune 22, 2026\u003c\/time\u003e · \u003cstrong\u003eSources:\u003c\/strong\u003e OSHA Annotated PEL tables, OSHA 29 CFR 1910, ACGIH Threshold Limit Values, manufacturer data sheets.\u003c\/div\u003e\n\u003cdiv style=\"background:#2a2520;border-left:4px solid #ff9800;padding:16px 20px;margin:18px 0;color:#f5e6d3;font-size:0.92em;\"\u003e\n\u003cstrong style=\"color:#ffb74d;\"\u003eDisclosure.\u003c\/strong\u003e WC Safety participates in the Amazon Associates Program (tag wcsafety04-20). Buyer guidance only, not medical, legal or regulatory advice — confirm gas-detection requirements against the applicable OSHA standard and, for commercial programs, a Certified Industrial Hygienist (CIH).\u003c\/div\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n \"@context\": \"https:\/\/schema.org\",\n \"@graph\": [\n  {\n   \"@type\": \"CollectionPage\",\n   \"@id\": \"https:\/\/wcsafety.com\/collections\/nitrogen-dioxide-detectors#collection\",\n   \"name\": \"Nitrogen Dioxide (NO2) Detectors\",\n   \"description\": \"Shop nitrogen dioxide (NO2) detectors for diesel exhaust, welding and firing ranges. Handheld NO2 monitors with low-range sensors. Compare and choose.\",\n   \"url\": \"https:\/\/wcsafety.com\/collections\/nitrogen-dioxide-detectors\",\n   \"isPartOf\": {\n    \"@type\": \"WebSite\",\n    \"name\": \"WC Safety\",\n    \"url\": \"https:\/\/wcsafety.com\"\n   },\n   \"breadcrumb\": {\n    \"@id\": \"https:\/\/wcsafety.com\/collections\/nitrogen-dioxide-detectors#breadcrumb\"\n   }\n  },\n  {\n   \"@type\": \"FAQPage\",\n   \"mainEntity\": [\n    {\n     \"@type\": \"Question\",\n     \"name\": \"What detects nitrogen dioxide?\",\n     \"acceptedAnswer\": {\n      \"@type\": \"Answer\",\n      \"text\": \"A dedicated NO2 detector with an electrochemical sensor — a standard 4-gas monitor does not cover NO2.\"\n     }\n    },\n    {\n     \"@type\": \"Question\",\n     \"name\": \"Where is NO2 detection needed?\",\n     \"acceptedAnswer\": {\n      \"@type\": \"Answer\",\n      \"text\": \"Diesel-exhaust areas (garages, depots, mining), welding and metal fabrication, indoor firing ranges, and combustion\/boiler areas.\"\n     }\n    },\n    {\n     \"@type\": \"Question\",\n     \"name\": \"What is the OSHA limit for NO2?\",\n     \"acceptedAnswer\": {\n      \"@type\": \"Answer\",\n      \"text\": \"A ceiling of about 5 ppm per the OSHA PEL; ACGIH lists a lower TWA. NO2 is toxic at low levels.\"\n     }\n    },\n    {\n     \"@type\": \"Question\",\n     \"name\": \"Is NO2 heavier than air?\",\n     \"acceptedAnswer\": {\n      \"@type\": \"Answer\",\n      \"text\": \"Yes — nitrogen dioxide is heavier than air and concentrates near combustion sources like diesel engines and welding.\"\n     }\n    },\n    {\n     \"@type\": \"Question\",\n     \"name\": \"Is NO2 the same as nitric oxide (NO)?\",\n     \"acceptedAnswer\": {\n      \"@type\": \"Answer\",\n      \"text\": \"No — they are different nitrogen oxides. NO2 (nitrogen dioxide) is the more acutely toxic and the one usually monitored for exposure.\"\n     }\n    },\n    {\n     \"@type\": \"Question\",\n     \"name\": \"Do NO2 sensors need calibration?\",\n     \"acceptedAnswer\": {\n      \"@type\": \"Answer\",\n      \"text\": \"Yes — verify response against NO2 calibration gas periodically and replace the sensor per the manufacturer's guidance.\"\n     }\n    },\n    {\n     \"@type\": \"Question\",\n     \"name\": \"Can I use it for confined-space entry?\",\n     \"acceptedAnswer\": {\n      \"@type\": \"Answer\",\n      \"text\": \"NO2 is one hazard; entry also needs O2, combustible and toxic testing with a portable 4-gas instrument.\"\n     }\n    },\n    {\n     \"@type\": \"Question\",\n     \"name\": \"Portable or fixed NO2 detection?\",\n     \"acceptedAnswer\": {\n      \"@type\": \"Answer\",\n      \"text\": \"Handheld units cover surveys and exposure; fixed NO2 detection exists for enclosed diesel and combustion areas. See Fixed Gas Detection Systems.\"\n     }\n    },\n    {\n     \"@type\": \"Question\",\n     \"name\": \"Is NO2 a diesel-exhaust marker?\",\n     \"acceptedAnswer\": {\n      \"@type\": \"Answer\",\n      \"text\": \"Yes — NO2 is a key component of diesel exhaust, so NO2 monitoring is common in garages, depots and enclosed diesel-equipment areas.\"\n     }\n    },\n    {\n     \"@type\": \"Question\",\n     \"name\": \"How dangerous is NO2?\",\n     \"acceptedAnswer\": {\n      \"@type\": \"Answer\",\n      \"text\": \"Nitrogen dioxide irritates and damages the respiratory tract even at low concentrations, which is why the OSHA ceiling is around 5 ppm.\"\n     }\n    }\n   ]\n  },\n  {\n   \"@type\": \"BreadcrumbList\",\n   \"@id\": \"https:\/\/wcsafety.com\/collections\/nitrogen-dioxide-detectors#breadcrumb\",\n   \"itemListElement\": [\n    {\n     \"@type\": \"ListItem\",\n     \"position\": 1,\n     \"name\": \"Home\",\n     \"item\": \"https:\/\/wcsafety.com\/\"\n    },\n    {\n     \"@type\": \"ListItem\",\n     \"position\": 2,\n     \"name\": \"Gas Detectors\",\n     \"item\": \"https:\/\/wcsafety.com\/collections\/gas-detectors\"\n    },\n    {\n     \"@type\": \"ListItem\",\n     \"position\": 3,\n     \"name\": \"Nitrogen Dioxide (NO2) Detectors\"\n    }\n   ]\n  }\n ]\n}\n\u003c\/script\u003e","products":[{"product_id":"smart-sensor-no2-gas-detector","title":"Smart Sensor NO2 Gas Detector — Handheld Nitrogen Dioxide Monitor (0-20 ppm)","description":"\u003c!-- PRODUCT B07P8RVM1T | tag portable-gas-detector | TODO: add matching Product Review + best-of guide links when those silo layers exist --\u003e\n\n\u003cdiv style=\"background:#1a1a1a;border-left:4px solid #ff9800;padding:14px 18px;margin:0 0 18px 0;color:#f5e6d3;font-size:0.95em;\"\u003e\n\u003cstrong style=\"color:#ffb74d;\"\u003eEditor’s note:\u003c\/strong\u003e the Smart Sensor NO2 gas detector is one of the instruments we curate in our \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"Portable Gas Detectors\"\u003ePortable Gas Detectors\u003c\/a\u003e buyer’s hub. Compare it with the \u003ca href=\"\/products\/forensics-hydrogen-cyanide-detector-hcn\" title=\"Forensics HCN Detector\"\u003eForensics HCN Detector\u003c\/a\u003e below before you order.\u003c\/div\u003e\n\n\u003ch2 id=\"top\"\u003eSmart Sensor NO2 Gas Detector — Handheld Nitrogen Dioxide Monitor\u003c\/h2\u003e\n\n\u003cp\u003eThe \u003cstrong\u003eSmart Sensor NO2 gas detector\u003c\/strong\u003e measures nitrogen dioxide from 0-20 ppm on a rechargeable handheld — a \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"portable gas detector\"\u003eportable gas detector\u003c\/a\u003e for diesel exhaust, welding fume and firing ranges, covering a toxic gas the four-gas set doesn’t.\u003c\/p\u003e\n\n\u003cp style=\"font-size:0.9em;color:#bdae9d;margin:10px 0 18px 0;\"\u003eJump to: \u003ca href=\"#features\" style=\"color:#ffb74d;\"\u003eFeatures\u003c\/a\u003e · \u003ca href=\"#specs\" style=\"color:#ffb74d;\"\u003eSpecs\u003c\/a\u003e · \u003ca href=\"#compatibility\" style=\"color:#ffb74d;\"\u003eWhat it detects\u003c\/a\u003e · \u003ca href=\"#comparison\" style=\"color:#ffb74d;\"\u003eComparison\u003c\/a\u003e · \u003ca href=\"#faq\" style=\"color:#ffb74d;\"\u003eFAQ\u003c\/a\u003e\u003c\/p\u003e\n\n\u003cp\u003eThe Smart Sensor NO2 Gas Detector is a handheld, rechargeable nitrogen dioxide monitor (0-20 ppm) with an LCD and audible, visual and vibration alarms for diesel-exhaust and welding environments.\u003c\/p\u003e\n\n\u003ch3 id=\"features\"\u003eKey features\u003c\/h3\u003e\n\n\u003cul\u003e\n\u003cli\u003eMeasures nitrogen dioxide (NO2) from 0-20 ppm — a toxic gas outside the 4-gas set\u003c\/li\u003e\n\u003cli\u003eRechargeable Li-battery with LCD readout\u003c\/li\u003e\n\u003cli\u003eAudible, visual and vibration alarms\u003c\/li\u003e\n\u003cli\u003eCompact 200 g handheld\u003c\/li\u003e\n\u003cli\u003eFor diesel-exhaust, welding-fume and firing-range NO2\u003c\/li\u003e\n\u003cli\u003eCovers a hazard a standard four-gas monitor doesn't detect\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cdiv style=\"display:flex;gap:14px;flex-wrap:wrap;margin:18px 0;\"\u003e\n\u003cdiv style=\"flex:1;min-width:240px;background:#1b3a2a;border:1px solid #4caf50;border-radius:6px;padding:14px 18px;\"\u003e\n\u003cstrong style=\"color:#81c784;\"\u003ePros\u003c\/strong\u003e\u003cul style=\"margin:8px 0 0 0;\"\u003e\n\u003cli\u003eDedicated NO2 detection\u003c\/li\u003e\n\u003cli\u003eLow 0-20 ppm range for NO2 limits\u003c\/li\u003e\n\u003cli\u003eRechargeable\u003c\/li\u003e\n\u003cli\u003eTriple alarm modes\u003c\/li\u003e\n\u003cli\u003eAffordable for a specialty toxic\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"flex:1;min-width:240px;background:#3a1e1e;border:1px solid #ef5350;border-radius:6px;padding:14px 18px;\"\u003e\n\u003cstrong style=\"color:#e57373;\"\u003eCons\u003c\/strong\u003e\u003cul style=\"margin:8px 0 0 0;\"\u003e\n\u003cli\u003eNitrogen dioxide only\u003c\/li\u003e\n\u003cli\u003eValue brand (Smart Sensor)\u003c\/li\u003e\n\u003cli\u003eNo NIST certificate standard\u003c\/li\u003e\n\u003cli\u003eSensor needs periodic verification\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003ch3 id=\"specs\"\u003eSpecifications\u003c\/h3\u003e\n\n\u003cdiv style=\"overflow-x:auto;\"\u003e\u003ctable style=\"width:100%;border-collapse:collapse;background:#1a1a1a;margin:14px 0;\"\u003e\n\u003cthead\u003e\u003ctr style=\"background:#2a2a2a;\"\u003e\n\u003cth style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;text-align:left;\"\u003eSpecification\u003c\/th\u003e\n\u003cth style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;text-align:left;\"\u003eDetail\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eGas detected\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eNitrogen dioxide (NO2)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eRange\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003e0-20 ppm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eDisplay\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eLCD\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eAlarms\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eAudible, visual \u0026amp; vibration\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003ePower\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eRechargeable Li-battery\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eWeight\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003e200 g\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eColor\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eOrange\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003c\/div\u003e\n\n\u003ch3\u003eWhere the Smart Sensor NO2 Detector fits\u003c\/h3\u003e\n\n\u003cul\u003e\n\u003cli\u003eDiesel-exhaust areas (garages, depots)\u003c\/li\u003e\n\u003cli\u003eWelding and metal fabrication\u003c\/li\u003e\n\u003cli\u003eIndoor firing ranges\u003c\/li\u003e\n\u003cli\u003eCombustion and boiler areas\u003c\/li\u003e\n\u003cli\u003eConfined-space NO2 risk\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"compatibility\"\u003eWhat the Smart Sensor NO2 Detector detects (and what it doesn’t)\u003c\/h2\u003e\n\n\u003cp\u003eIt detects \u003cstrong\u003enitrogen dioxide (NO2) only\u003c\/strong\u003e — not O2, combustibles, CO or H2S. For the four atmospheric gases use a \u003ca href=\"\/products\/forensics-detectors-4-gas-meter-confined-space\" title=\"Forensics 4 Gas Meter\"\u003eForensics 4 Gas Meter\u003c\/a\u003e; for other single toxics see the \u003ca href=\"\/products\/forensics-chlorine-analyzer-cl2\" title=\"Chlorine\"\u003eChlorine\u003c\/a\u003e or \u003ca href=\"\/products\/forensics-sulfur-dioxide-analyzer-so2\" title=\"SO2\"\u003eSO2\u003c\/a\u003e analyzers. NO2 is heavier than air and comes mainly from combustion (diesel exhaust, welding). Verify response against NO2 calibration gas periodically.\u003c\/p\u003e\n\n\u003cp\u003eCross-shopping? This unit sits in our \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"Portable Gas Detectors\"\u003ePortable Gas Detectors\u003c\/a\u003e hub alongside \u003ca href=\"\/products\/forensics-hydrogen-cyanide-detector-hcn\" title=\"Forensics HCN Detector\"\u003eForensics HCN Detector\u003c\/a\u003e, \u003ca href=\"\/products\/forensics-hydrogen-gas-analyzer-portable\" title=\"Forensics Hydrogen Analyzer\"\u003eForensics Hydrogen Analyzer\u003c\/a\u003e, \u003ca href=\"\/products\/forensics-chlorine-analyzer-cl2\" title=\"Forensics Chlorine Analyzer\"\u003eForensics Chlorine Analyzer\u003c\/a\u003e, \u003ca href=\"\/products\/forensics-sulfur-dioxide-analyzer-so2\" title=\"Forensics SO2 Analyzer\"\u003eForensics SO2 Analyzer\u003c\/a\u003e. For other gas-detection form factors see \u003ca href=\"\/collections\/personal-gas-detectors\" title=\"Personal \u0026amp; Wearable Gas Detectors\"\u003ePersonal \u0026amp; Wearable Gas Detectors\u003c\/a\u003e, \u003ca href=\"\/collections\/fixed-gas-detection-systems\" title=\"Fixed Gas Detection Systems\"\u003eFixed Gas Detection Systems\u003c\/a\u003e, \u003ca href=\"\/collections\/area-gas-monitors\" title=\"Area \u0026amp; Transportable Gas Monitors\"\u003eArea \u0026amp; Transportable Gas Monitors\u003c\/a\u003e, or browse the full \u003ca href=\"\/collections\/gas-detectors\" title=\"Gas Detectors\"\u003eGas Detectors\u003c\/a\u003e range.\u003c\/p\u003e\n\n\u003ch2 id=\"comparison\"\u003eWhere the Smart Sensor NO2 detector fits\u003c\/h2\u003e\n\n\u003cp\u003eNO2 detection covers diesel-exhaust and welding hazards a four-gas monitor misses. For other single toxics, the \u003ca href=\"\/products\/forensics-chlorine-analyzer-cl2\" title=\"Forensics Chlorine\"\u003eForensics Chlorine\u003c\/a\u003e and \u003ca href=\"\/products\/forensics-sulfur-dioxide-analyzer-so2\" title=\"SO2\"\u003eSO2\u003c\/a\u003e analyzers cover Cl2 and SO2; for the four atmospheric gases use a \u003ca href=\"\/products\/forensics-detectors-4-gas-meter-confined-space\" title=\"4 Gas Meter\"\u003e4 Gas Meter\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003eChoose the \u003cstrong\u003eSmart Sensor NO2 Detector\u003c\/strong\u003e for diesel-exhaust, welding and firing-range nitrogen dioxide.\u003c\/li\u003e\n\u003cli\u003eFor chlorine or SO2, see the \u003ca href=\"\/products\/forensics-chlorine-analyzer-cl2\" title=\"Chlorine\"\u003eChlorine\u003c\/a\u003e and \u003ca href=\"\/products\/forensics-sulfur-dioxide-analyzer-so2\" title=\"SO2\"\u003eSO2\u003c\/a\u003e analyzers.\u003c\/li\u003e\n\u003cli\u003eFor the four atmospheric gases, use a \u003ca href=\"\/products\/forensics-detectors-4-gas-meter-confined-space\" title=\"4 Gas Meter\"\u003e4 Gas Meter\u003c\/a\u003e.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"faq\"\u003eFrequently asked questions\u003c\/h2\u003e\n\n\u003ch3\u003eWhat does the Smart Sensor NO2 detector measure?\u003c\/h3\u003e\u003cp\u003eNitrogen dioxide (NO2) from 0-20 ppm. It does not measure O2, LEL, CO or H2S — use a \u003ca href=\"\/products\/forensics-detectors-4-gas-meter-confined-space\" title=\"4 gas meter\"\u003e4 gas meter\u003c\/a\u003e for those.\u003c\/p\u003e\n\u003ch3\u003eWhere is NO2 detection needed?\u003c\/h3\u003e\u003cp\u003eDiesel-exhaust areas (garages, depots, mining), welding and metal fabrication, indoor firing ranges, and combustion\/boiler areas.\u003c\/p\u003e\n\u003ch3\u003eWhat is the OSHA limit for nitrogen dioxide?\u003c\/h3\u003e\u003cp\u003eOSHA sets a ceiling around 5 ppm and ACGIH lists a low TWA; NO2 is toxic at low levels, so a low range and low alarms matter. Confirm current values for your program.\u003c\/p\u003e\n\u003ch3\u003eIs NO2 heavier than air?\u003c\/h3\u003e\u003cp\u003eYes — nitrogen dioxide is heavier than air and comes mainly from combustion sources like diesel engines and welding.\u003c\/p\u003e\n\u003ch3\u003eIs it rechargeable?\u003c\/h3\u003e\u003cp\u003eYes — it uses a rechargeable Li-battery with an LCD readout.\u003c\/p\u003e\n\u003ch3\u003eWhat alarms does it have?\u003c\/h3\u003e\u003cp\u003eAudible, visual and vibration alarms trigger when NO2 exceeds the set point.\u003c\/p\u003e\n\u003ch3\u003eDoes it come NIST calibrated?\u003c\/h3\u003e\u003cp\u003eIt is factory-set; for a NIST-certified specialty analyzer, the Forensics models (e.g. \u003ca href=\"\/products\/forensics-chlorine-analyzer-cl2\" title=\"Chlorine\"\u003eChlorine\u003c\/a\u003e) include certificates. Verify NO2 response against calibration gas periodically.\u003c\/p\u003e\n\u003ch3\u003eCan it detect other gases?\u003c\/h3\u003e\u003cp\u003eNo — NO2 only. For chlorine use the \u003ca href=\"\/products\/forensics-chlorine-analyzer-cl2\" title=\"Chlorine Analyzer\"\u003eChlorine Analyzer\u003c\/a\u003e; for SO2 the \u003ca href=\"\/products\/forensics-sulfur-dioxide-analyzer-so2\" title=\"SO2 Analyzer\"\u003eSO2 Analyzer\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eIs it good for diesel exhaust monitoring?\u003c\/h3\u003e\u003cp\u003eYes — NO2 is a key marker of diesel exhaust, so this detector suits garages, depots and enclosed diesel-equipment areas.\u003c\/p\u003e\n\u003ch3\u003eIs it in stock and how does it ship?\u003c\/h3\u003e\u003cp\u003eUse the Amazon buy button for current availability and delivery timing through our fulfillment partner.\u003c\/p\u003e\n\u003ch3\u003eHow do I keep it accurate?\u003c\/h3\u003e\u003cp\u003eVerify response against NO2 calibration gas periodically and replace the sensor per the manufacturer's guidance.\u003c\/p\u003e\n\u003ch3\u003eCan I use it for confined-space entry?\u003c\/h3\u003e\u003cp\u003eNO2 is one hazard; entry also needs O2, combustible and toxic testing with a \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"portable 4-gas instrument\"\u003eportable 4-gas instrument\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003cdiv style=\"background:#1a1a1a;border:1px solid #3a3a3a;border-radius:6px;padding:16px 18px;margin:22px 0;\"\u003e\n\u003cp style=\"margin:0 0 10px 0;color:#f5e6d3;\"\u003eReady to order the \u003cstrong\u003eSmart Sensor NO2 gas detector\u003c\/strong\u003e? Add it to your cart above, or check the current Amazon price below. Compare it against the rest of our \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"Portable Gas Detectors\"\u003ePortable Gas Detectors\u003c\/a\u003e lineup before you buy.\u003c\/p\u003e\n\u003cp style=\"display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin:0;\"\u003e\u003ca href=\"https:\/\/www.amazon.com\/dp\/B07P8RVM1T?tag=wcsafety04-20\" rel=\"sponsored nofollow noopener\" target=\"_blank\" style=\"display:inline-block;background:#FFD814;color:#0F1111;padding:13px 26px;text-decoration:none;font-weight:bold;border-radius:4px;border:1px solid #FCD200;\"\u003eCHECK PRICE ON AMAZON →\u003c\/a\u003e\u003cspan style=\"font-size:0.8em;color:#bdae9d;\"\u003eAs an Amazon Associate, WC Safety earns from qualifying purchases.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv style=\"background:#1a2733;border:1px dashed #4fc3f7;padding:16px 20px;margin:30px 0 18px 0;color:#cfd8dc;font-size:0.92em;\"\u003e\n  \u003cstrong style=\"color:#4fc3f7;\"\u003eWhy trust this Smart Sensor page?\u003c\/strong\u003e WC Safety is an independent industrial safety-equipment retailer serving safety managers, procurement teams and field supervisors. The specifications here are taken from the manufacturer’s published listing for Smart Sensor NO2 Detector and framed against \u003ca href=\"https:\/\/www.osha.gov\/laws-regs\/regulations\/standardnumber\/1910\/1910.146\" rel=\"noopener\" target=\"_blank\" style=\"color:#4fc3f7;\"\u003eOSHA 29 CFR 1910.146\u003c\/a\u003e and \u003ca href=\"https:\/\/www.osha.gov\/annotated-pels\" rel=\"noopener\" target=\"_blank\" style=\"color:#4fc3f7;\"\u003eOSHA Permissible Exposure Limits\u003c\/a\u003e. Disclosed: WC Safety earns Amazon affiliate commissions on outbound clicks; that does not influence the specs shown or our lineup.\n\u003c\/div\u003e\n\u003cdiv style=\"background:#1a2733;border-left:4px solid #4fc3f7;padding:18px 22px;margin:18px 0;color:#cfd8dc;font-size:0.92em;\"\u003e\n  \u003cstrong style=\"color:#4fc3f7;\"\u003eBy Steven Eaton, WC Safety Editorial\u003c\/strong\u003e — Industrial safety-equipment desk · specialization: atmospheric monitoring, gas detection and instrument selection.\u003cbr\u003e\n  \u003cstrong\u003eLast updated:\u003c\/strong\u003e \u003ctime datetime=\"2026-06-22\"\u003eJune 22, 2026\u003c\/time\u003e · \u003cstrong\u003eSources reviewed:\u003c\/strong\u003e manufacturer product listing \u0026amp; specifications, OSHA 29 CFR 1910.146, OSHA Annotated PEL tables, ACGIH Threshold Limit Values.\u003cbr\u003e\n  \u003cstrong\u003eEditorial standard:\u003c\/strong\u003e \u003cem\u003eZero sponsored listings. No manufacturer input. Specs verified against the manufacturer’s published data.\u003c\/em\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"background:#1a2733;border-left:4px solid #4fc3f7;padding:16px 20px;margin:18px 0;color:#cfd8dc;font-size:0.92em;\"\u003e\n  \u003cstrong style=\"color:#4fc3f7;\"\u003eHow this page is maintained.\u003c\/strong\u003e Specifications and pricing are reviewed against the manufacturer’s current listing and re-checked whenever the lineup changes. Gas-detection guidance follows \u003ca href=\"https:\/\/www.osha.gov\/laws-regs\/regulations\/standardnumber\/1910\/1910.146\" rel=\"noopener\" target=\"_blank\" style=\"color:#4fc3f7;\"\u003eOSHA 1910.146\u003c\/a\u003e and \u003ca href=\"https:\/\/www.osha.gov\/annotated-pels\" rel=\"noopener\" target=\"_blank\" style=\"color:#4fc3f7;\"\u003eOSHA PELs\u003c\/a\u003e, cross-referenced with ACGIH TLVs.\n\u003c\/div\u003e\n\u003cdiv style=\"background:#2a2520;border-left:4px solid #ff9800;padding:16px 20px;margin:18px 0;color:#f5e6d3;font-size:0.92em;\"\u003e\n  \u003cstrong style=\"color:#ffb74d;\"\u003eDisclosure.\u003c\/strong\u003e WC Safety participates in the Amazon Associates Program and earns commissions on qualifying purchases through outbound links on this page (tag wcsafety04-20). We are not sponsored by any instrument manufacturer. This page is buyer guidance, not medical, legal or regulatory advice — confirm gas-detection requirements for your site against the applicable OSHA standard and, for commercial monitoring programs, a Certified Industrial Hygienist (CIH).\n\u003c\/div\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\"@context\": \"https:\/\/schema.org\", \"@graph\": [{\"@type\": \"Product\", \"@id\": \"https:\/\/wcsafety.com\/products\/smart-sensor-no2-gas-detector#product\", \"name\": \"Smart Sensor NO2 Gas Detector — Handheld Nitrogen Dioxide Monitor (0-20 ppm)\", \"description\": \"Smart Sensor NO2 gas detector — handheld nitrogen dioxide monitor, 0-20 ppm, rechargeable with LCD and alarms for diesel exhaust. Order at WC Safety.\", \"sku\": \"B07P8RVM1T\", \"mpn\": \"AS8905-NO2\", \"image\": [\"https:\/\/wcsafety.com\/cdn\/shop\/products\/smart-sensor-no2-gas-detector.jpg\"], \"brand\": {\"@type\": \"Brand\", \"name\": \"Smart Sensor\"}, \"category\": \"Portable Gas Detector\", \"isPartOf\": {\"@type\": \"CollectionPage\", \"@id\": \"https:\/\/wcsafety.com\/collections\/portable-gas-detectors#collection\", \"name\": \"Portable Gas Detectors\", \"url\": \"https:\/\/wcsafety.com\/collections\/portable-gas-detectors\"}, \"isRelatedTo\": [{\"@type\": \"Product\", \"name\": \"Forensics Hydrogen Cyanide (HCN) Detector\", \"url\": \"https:\/\/wcsafety.com\/products\/forensics-hydrogen-cyanide-detector-hcn\"}, {\"@type\": \"Product\", \"name\": \"Forensics Hydrogen Gas Analyzer (Portable)\", \"url\": \"https:\/\/wcsafety.com\/products\/forensics-hydrogen-gas-analyzer-portable\"}, {\"@type\": \"Product\", \"name\": \"Forensics Chlorine (Cl2) Analyzer\", \"url\": \"https:\/\/wcsafety.com\/products\/forensics-chlorine-analyzer-cl2\"}, {\"@type\": \"Product\", \"name\": \"Forensics Sulfur Dioxide (SO2) Analyzer\", \"url\": \"https:\/\/wcsafety.com\/products\/forensics-sulfur-dioxide-analyzer-so2\"}, {\"@type\": \"Product\", \"name\": \"Forensics Ammonia (NH3) Detector\", \"url\": \"https:\/\/wcsafety.com\/products\/forensics-ammonia-detector-nh3\"}, {\"@type\": \"Product\", \"name\": \"Forensics Detectors 4 Gas Meter\", \"url\": \"https:\/\/wcsafety.com\/products\/forensics-detectors-4-gas-meter-confined-space\"}], \"offers\": {\"@type\": \"Offer\", \"url\": \"https:\/\/wcsafety.com\/products\/smart-sensor-no2-gas-detector\", \"priceCurrency\": \"USD\", \"price\": \"294.50\", \"availability\": \"https:\/\/schema.org\/InStock\", \"seller\": {\"@type\": \"Organization\", \"name\": \"WC Safety\"}}}, {\"@type\": \"BreadcrumbList\", \"@id\": \"https:\/\/wcsafety.com\/products\/smart-sensor-no2-gas-detector#breadcrumb\", \"itemListElement\": [{\"@type\": \"ListItem\", \"position\": 1, \"name\": \"Home\", \"item\": \"https:\/\/wcsafety.com\/\"}, {\"@type\": \"ListItem\", \"position\": 2, \"name\": \"Gas Detectors\", \"item\": \"https:\/\/wcsafety.com\/collections\/gas-detectors\"}, {\"@type\": \"ListItem\", \"position\": 3, \"name\": \"Portable Gas Detectors\", \"item\": \"https:\/\/wcsafety.com\/collections\/portable-gas-detectors\"}, {\"@type\": \"ListItem\", \"position\": 4, \"name\": \"Smart Sensor NO2 Gas Detector — Handheld Nitrogen Dioxide Monitor (0-20 ppm)\"}]}, {\"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"What does the Smart Sensor NO2 detector measure?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Nitrogen dioxide (NO2) from 0-20 ppm. It does not measure O2, LEL, CO or H2S — use a 4 gas meter for those.\"}}, {\"@type\": \"Question\", \"name\": \"Where is NO2 detection needed?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Diesel-exhaust areas (garages, depots, mining), welding and metal fabrication, indoor firing ranges, and combustion\/boiler areas.\"}}, {\"@type\": \"Question\", \"name\": \"What is the OSHA limit for nitrogen dioxide?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"OSHA sets a ceiling around 5 ppm and ACGIH lists a low TWA; NO2 is toxic at low levels, so a low range and low alarms matter. Confirm current values for your program.\"}}, {\"@type\": \"Question\", \"name\": \"Is NO2 heavier than air?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Yes — nitrogen dioxide is heavier than air and comes mainly from combustion sources like diesel engines and welding.\"}}, {\"@type\": \"Question\", \"name\": \"Is it rechargeable?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Yes — it uses a rechargeable Li-battery with an LCD readout.\"}}, {\"@type\": \"Question\", \"name\": \"What alarms does it have?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Audible, visual and vibration alarms trigger when NO2 exceeds the set point.\"}}, {\"@type\": \"Question\", \"name\": \"Does it come NIST calibrated?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"It is factory-set; for a NIST-certified specialty analyzer, the Forensics models (e.g. Chlorine) include certificates. Verify NO2 response against calibration gas periodically.\"}}, {\"@type\": \"Question\", \"name\": \"Can it detect other gases?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"No — NO2 only. 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