Director of Public Health Annual Report 2018: Healthy places

Air pollution is a mixture of particles and gases that damage health, the environment and the economy. The most important pollutants with respect to health are particulate matter (PM) and nitrogen dioxide. Particulate matter is classified by size and includes PM10 and PM2.5 which comprise all particles smaller than 10 microns and 2.5 microns respectively. PM2.5 is most strongly linked to health outcomes as at this size the particles can be inhaled deep into the lungs. The very small particles PM0.1 once inhaled can pass directly into the bloodstream. The particles can be composed of combustion products, abrasion of engine components, brakes and tyres on road surfaces or generated during construction and agricultural processes. In urban pollution hotspots, particularly those close to roads, the source is mainly from traffic and the particles include soot, part burnt petrol and diesel and compounds that form benzene based carcinogens and waste matter from road surfaces. There are considerable differences in emissions between vehicles but on average diesel exhaust contains up to 30 times more PM than petrol. In the countryside agriculture and upwind industries make a larger contribution to air pollution. Nationally, 38% of PM2.5 is produced by households burning wood, coal and other solids fuels in open fires and stoves.

Nitrogen dioxide and related oxides of nitrogen are gases produced by combustion. In areas where the UK is exceeding recommended limits 80% of the emissions are due to transport, the largest source of which is diesel cars and vans.

Air pollution is the largest environmental risk to the public’s health contributing to cardiovascular disease, lung cancer and respiratory disease. More than one in every 20 deaths in the UK is attributed to long term exposure to PM2.5 air pollutants. That is the equivalent of approximately 25,000 deaths per year.

Long term exposure to PM contributes to the development of cardiovascular disease, lung cancer and respiratory disease and increases the risk of death. Exposure to elevated levels of PM2.5 increases the risk of death and shortens life expectancy by several months to a few years. Short term exposure to elevated PM2.5 levels can trigger wheezing and exacerbations of asthma and bronchitis, heart attacks and heart rhythm disturbances and strokes and has been linked to an increase in hospital admissions as well as deaths. There is also emerging evidence linking long term exposure to PM2.5 to the progression of Alzheimer’s and Parkinson’s disease, diabetes, low birthweight and developmental outcomes.

Nitrogen dioxide (NO2) at high concentrations is a respiratory irritant that can cause inflammation of the airways and shortness of breath. Studies have shown links between high concentrations of NO2 and impaired lung development and respiratory infections in children and adverse effects on adult lung function.

Older people, children and those with cardiovascular or respiratory disease are particularly vulnerable to the effects of air pollution. Exposure to air pollution is also unevenly distributed across the population with deprived communities more likely to be living near busy polluting roads. Air pollution varies substantially over small distances being typically highest near the source and can decline rapidly further away. Air pollution levels are typically as high within vehicles as outside so higher levels of air pollution are experienced not only by those who live or work on busy roads but also those who drive for a living.

The costs to society of air pollution are similar to those caused by obesity and smoking, with health related costs estimated between £22bn and £67bn and costs due to lost economic productivity estimated at almost £0.8bn.

Noise is an often underestimated threat that can cause a number of short- and long-term health problems. Excessive noise seriously harms human health and interferes with people’s daily activities at school, at work, at home and during leisure time.

It impacts on both physical and mental health through sleep disturbance and increased stress. It is estimated that the direct health impact of noise pollution costs the UK economy over one billion pounds per year.

Noise pollution is associated with poor sleep and stress, increased blood pressure and increased risk of conditions such as heart attack, stroke and dementia. In children, exposure to noise pollution can have a negative effect on development and education with evidence showing poorer educational attainment and worse health in children exposed to higher levels of noise pollution. Children exposed to noise have poorer concentration and for every 5 decibel increase in average noise that children are exposed to, reading age decreases by two months.

In the UK, about half of the UK population live in areas where daytime sound levels exceed the recommended limit, causing adverse impacts on health. About two-thirds of the population live in areas where the night-time guidelines recommenced by the WHO are exceeded.

Outside night noise levels of 55 decibels (dB) plus exposure is considered increasingly dangerous for public health. About 40% of the population in EU countries are exposed to road traffic noise at levels exceeding 55 (dB) and 20% are exposed to levels exceeding 65 (dB) during the daytime; and more than 30% is exposed to levels exceeding 55 (dB) at night.

Noise pollution disproportionately affects the most vulnerable in society, with homes in more deprived communities exposed to higher levels of noise pollution from busy roads. In addition, the impacts of noise pollution are greater among children and older people.

People value quiet areas, with 91% identifying the importance of protecting quiet areas from an increase in noise. In Buckinghamshire, there were over 1500 noise complaints in 2014/15. The rate of noise complaints per 1000 residents is highest in Wycombe District (4.0) followed by Chiltern (3.5), Aylesbury Vale (2.0) and South Bucks (1.6).