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How clean is the air you breathe?

18 January 2016

Indoor air quality must be monitored to protect workers’ respiratory health. Dr Steve Goodman, product specialist manager, Shawcity highlights the dangers that may be present in every breath you take.

Indoor air quality is increasingly a pressing issue for many industries, particularly with regard to Volatile Organic Compounds (VOCs) and oxides of nitrogen (NOx).

VOCs are often associated with Sick Building Syndrome. Within the indoor environment they constitute the principal class of contaminants that can be found, consisting of a complex mixture of between 50 and 300 different types of organic compound.

The sources of most VOCs are products used in construction, finishing and cleaning products; paints, adhesives, sealants, flooring, processed woods and surface finishings. Other sources include furniture, office electronics, personal care/hygiene products and other such materials brought into a building by its occupants. It is also possible for VOC contaminants to be drawn in from the outdoor environment, especially if a building is near roads or industrial activities.

In addition to VOCs it is recognised that particulates and inorganic gases are significant contributors to pollutants found within the indoor environment. Particulates often contain polyaromatic hydrocarbons (PAHs), metaliferous abrasion particles, sulfates and silicates; inorganic gases include oxides of nitrogen, sulphur and carbon; and there is an expansive list of organic compounds, which includes highly toxic compounds such as benzene, butadiene and formaldehyde.

The health effects of many volatile organics are still not fully understood, but in general it is known that the quantity, toxicity and length of time of exposure result in different outcomes. These effects are often associated with symptoms of irritation to eyes, nose and throat, headaches, dizziness, visual disorders and memory impairment.

Little is yet known about the health effects found in public/commercial buildings when mixtures of VOCs are present, but continuing research by private organisations and public bodies is helping to understand the risks posed.

Indoor environment studies have shown that the ambient total VOC concentration ranges from 0.2 to 5 milligrams per cubic metre of air (mg/m3), with a number reporting some environments reaching up to 25mg/m3. European Community target guideline values of between 0.2 – 0.3mg/m3 have been discussed.

Within the UK, the Building Research Establishment Environmental Assessment Methodology (BREEAM) has set out guideline values for VOCs, semi VOCs and aldehydes. Further to this, BREEAM sets limits on gases – including CO, CO2, NO, NO2, SO2 – as well as particles (mass concentration and size distribution). These are taken post-construction but pre-occupancy so that air quality can be confirmed before a building is put into use.

Recent significant research is being undertaken into the additional effects of NO2 and PM2.5 resulting from vehicles and permeating into the indoor environment in large urban conurbations. The effects of breathing in raised levels of nitrogen dioxide are the increased likelihood of respiratory problems resulting from inflamed lining of the lungs and reduced immunity to lung infections. Ultimately this leads to problems such as wheezing, coughing, colds, flu and bronchitis.

Increased levels of NO2 can have a significant impact on people with asthma, as it can cause more frequent and intense attacks.

Long term exposure to PM2.5 is understood to increase age-specific risk of death, particularly from cardiovascular causes. Exposure to high concentrations of PM2.5 can also exacerbate lung and heart conditions and increase numbers of deaths. Children and the elderly are known to be more susceptible to the health impacts from PM2.5 air pollution. Extreme air pollution involving these two major components have been on the rise, with London, Paris, Beijing, Singapore and many other cities being under increased threat. 

With the classification of diesel fume as a major cancer risk (International Agency for Research on Cancer, World Health Organisation) in 2012, diesel fume within enclosed spaces and indoor environments has come into sharp focus. This was reinforced by the Health and Safety Executive’s guidance note INDG 286 “Diesel Engine Exhaust Emissions” in the same year. This now requires any employer under the COSHH regulations to make a “suitable and sufficient assessment of the risks” and “prevent or adequately control the exposure”.