Ammonia is a pungent alkaline gas used as a cleaning agent in glass cleaners, multi-purpose sprays, floor polishes, and oven cleaners. While effective at cutting through grease and leaving streak-free glass surfaces, it is a potent respiratory irritant, a trigger for asthma, and a source of toxic chloramine gas when accidentally or deliberately mixed with bleach. Household exposure is highly underestimated because ammonia evaporates rapidly and is not perceived as a persistent hazard.
Where it's found
Glass and window cleaners are the most common domestic source — many branded products contain 5–10% ammonia. Multi-purpose surface sprays, bathroom cleaners, and floor polishes frequently contain ammonia. Some oven cleaners use ammonia-based formulations. Smelling salts and sal ammoniac are historical medical uses still found in some households. Cat urine generates ammonia naturally as it decomposes — homes with multiple cats and poor litter hygiene can develop measurable indoor ammonia levels independent of cleaning products.
Routes of exposure
Inhalation is the dominant route — ammonia volatilises readily at room temperature and concentrates in poorly ventilated indoor spaces. Spray application in enclosed bathrooms and kitchens generates high localised vapour concentrations. Skin and eye contact from splashes during cleaning. Mixing ammonia-based cleaners with bleach or hypochlorite products generates chloramine gas — a much more acutely toxic compound. People living with pets in ammonia-elevated environments have chronic low-level inhalation exposure.
Health concerns
Ammonia irritates the mucous membranes, airways, and eyes at low concentrations. At higher domestic concentrations it causes coughing, bronchoconstriction, and exacerbation of asthma. In people with pre-existing respiratory conditions, routine use of ammonia-based cleaners is associated with accelerated lung function decline. The acute hazard of mixing ammonia with bleach is well documented — chloramine gas formation can cause acute respiratory distress, pulmonary oedema, and in severe cases death in enclosed spaces. Chronic low-level ammonia inhalation is associated with increased airway reactivity and sensitisation.
Evidence
Respiratory irritancy of ammonia is firmly established across occupational and toxicological literature. Accelerated lung function decline in domestic cleaning product users is supported by the ECRHS and several cohort studies of professional cleaners. The chloramine formation hazard from bleach-ammonia mixing is chemically certain and clinically well documented via emergency poisoning case series.
Who's most at risk
People with asthma, COPD, or other respiratory conditions are most vulnerable to routine ammonia exposure from cleaning sprays. Children, whose airways are smaller and whose breathing rate per body weight is higher, absorb a proportionally greater respiratory dose during cleaning episodes. Professional cleaners with daily occupational exposure carry the highest cumulative burden.
Regulatory status
RegulationAmmonia is not specifically regulated in household cleaning products in the EU or UK by concentration limits, but products must carry appropriate hazard labelling under CLP Regulation (EC 1272/2008). Occupational exposure limits exist (UK WEL: 25 ppm STEL, 20 ppm TWA) but these apply to workplaces, not homes. Product labels are legally required to warn against mixing with bleach.
How to reduce your exposure
Switch to ammonia-free glass and surface cleaners — white vinegar diluted with water is highly effective for glass and streak-free surfaces. Always check whether a cleaning product contains ammonia before use, particularly before using it in the same space or on the same surfaces as bleach-based products. Open windows when using any spray cleaner. Never mix cleaning products. If you use ammonia-based products, ensure strong ventilation and limit exposure time in the cleaning space.
The nutrition connection
A switch away from chemical cleaning sprays — towards simple solutions of diluted white vinegar, bicarbonate of soda, and castile soap — eliminates ammonia exposure entirely and aligns with the Nutriofia principle of reducing total chemical load in the home environment. These alternatives are also lower in other VOCs and surfactants. For households with asthmatic family members, cleaning product choice is one of the most directly modifiable indoor air quality interventions available.