Health Effects of Winter Air Pollution

The major air pollution problems in Christchurch, Timaru and some other Canterbury towns is winter air pollution caused by suspended particulate. These are the small particles in the air which result mainly from combustion processes. They are less than 10 microns in diameter and are referred to as PM10 (particulate matter smaller than 10 microns).

The concentrations can be very high in built up areas during the winter months, particularly on still days when the particles are not dispersed by the wind. Under these conditions high numbers of small particles are readily inhaled and lodge in the lower lung causing a range of health problems.

One of the main problems with small particles (also called suspended particulate or PM10) is their size: they are so small that our breathing passages cannot get rid of them and we breathe them in. Air pollution has the greatest effect on children, the elderly and those with respiratory and heart problems.

 An independent study by the University of Otago  94kb has shown particulate pollution contributes to up to 70 deaths a year from respiratory problems. This, and overseas work, has shown a clear relationship with increased incidence of asthma, allergies and other conditions. Children and the elderly have been shown to be especially at risk.

Further analysis undertaken also indicates that particulate pollution results in 300,000 to 600,000 restricted activity days for the people of Christchurch. Results from a new survey in Christchurch show more than one-third of people said that they, or someone they knew, were affected by air pollution.

Here is what air pollution by PM10 can do to our health:

• Increase and aggravate asthma 
• Create disease in the airways of children 
• Increase respiratory illness in children 
• Damage the lungs 
• Increase deaths from respiratory and cardiovascular disease 
• Increase hospital admissions for lung and heart disease 
• Cause chest pain and nausea 
• Cause shortness of breath and (faster) laboured breathing 
• Permanently change lung structure

Respiratory physician Professor Ian Town says:

“Children and people with lung and heart disease are at greatest risk from the effects of suspended particulate, and it can make them ill,” says respiratory physician Professor Ian Town. “Our research clearly shows that people with asthma will have more episodes and require more treatment, including hospitalisation, when air pollution levels are higher,” he says. “More serious consequences are seen in people with chronic bronchitis, emphysema and heart disease. In these people air pollution can make their condition unstable, leading to an increase in hospital admissions and even death.”

How can the particles do so much damage?

When you breathe in suspended particulate matter (PM10) it can attack and inflame your tissues all the way down the respiratory tract. Because these particles are so small, they can go deep inside your lungs and damage the smallest airways called bronchioles. As the particles approach the cells lining the lungs, they are attacked by macrophages, part of the lungs' defence system. In turn, the macrophages trigger the release of inflammatory cells from the bone marrow. In some instances, toxic particles can destroy macrophages. Some particles make it all the way into the cells lining the lung, causing further inflammation that can hinder breathing.

Particles may also enter the bloodstream. Together with inflammatory mediators, they cause serious effects on the nervous system, as well as the heart and lungs.

Keeping Warm

For good health keeping warm in winter is just as important as clean air. A temperature of at least 18 degrees in living rooms and at least 21 degrees for older people and babies is recommended. Efficient clean heating which can be a clean air approved woodburner, a heat pump, flued gas heater, pellet burner or other clean heating appliance together with sufficient ceiling and underfloor insulation is the best strategy for a warm home at an affordable cost and clean air.