Ambient air quality
The key ambient air pollutants in the Auckland region are
- fine particulates (PM10 and PM2.5)
- carbon monoxide (CO)
- nitrogen dioxide (NO2)
- ozone (O3)
Vehicles are a major source of ambient air pollutants. Other contributing sources include industry and home heating. Both Auckland Regional Council and Ministry for the Environment have comprehensive information on air quality on their websites.
The Auckland Regional Public Health Service works to reduce potential and actual adverse effects of poor air quality upon the health of people in the region. In particular, ARPHS:
- redirect routine air quality complaints to the appropriate control authority;
- investigate in an audit manner, situations where an air quality issue has not been adequately addressed by the appropriate regulatory agency;
- review and comment upon air quality aspects of the Regional Air Plan and TLA District Plans;
- comment upon significant resource consent applications with an air quality component, and other applications if the regulatory agency requires clarification of a specific public health component to an application;
- investigate complaints of adverse indoor air quality (not occupational);
- investigate complaints of agricultural spray-drift as part of our response to human exposure to hazardous substances;
- investigate emerging issues of air quality with a distinct public health angle e.g. traffic pollution.
Fine particulate matter (PM10 and PM2.5)
Fine particulate matter refers to particles of less than 10 microns in diameter. Of public health importance are those of 10 and 2.5 microns in diameter, labelled as PM10and PM2.5, respectively. High concentrations of these pollutants have been associated mainly with exacerbation of asthma in asthmatics. Acute increases in PM10have been linked to increase in mortality, respiratory and cardiovascular hospital admissions, and incidence of chronic bronchitis, asthma attacks, lung function reduction, and restricted activity days. Fine particulates are of major public health concern as there is growing evidence that it is even smaller fraction, such as PM2.5, which is responsible for adverse health effects. The WHO believes that there is no safe limit for fine particulate matter.
Carbon monoxide (CO)
Carbon monoxide is formed from the incomplete combustion of fuels. CO binds to haemoglobin in the blood, reducing its oxygen-carrying capacity. It can result in an increase in symptoms of cardiovascular illness, and it can also cause neuro-behavioural effects such as impaired co-ordination, driving ability and cognitive performance.
Oxides of nitrogen (NOX)
Most nitrogen oxide is emitted as nitric oxide (NO) that has no major effects on human health. However, if NO is converted into nitrogen dioxide (NO2), it may cause a worsening of symptoms for those suffering from respiratory disorders such as asthma, cough, wheeze and breath shortness.
Volatile organic compounds (VOCs)
VOCs are a wide range of compounds emitted by various sources. Environmental exposure has been linked to chromosomal aberrations and depressions of blood-cell formation.
Ozone (O3)
Ground level of ozone is formed when VOCs react with nitrogen oxides in the presence of sunlight, and it has been shown to be associated with reduction in lung function, increased bronchial reactivity, and admissions to hospital.
The National Environmental Standards for some of the selected air pollutants are shown in Table 1.
For information on the WHO air quality guideline on selected air pollutants check the webpage of the World Health Organization.
| Contaminants | Threshold Concentration | Averaging Period | Permissible Excess |
|---|---|---|---|
| Carbon monoxide | 10 mg m-3 | 8-hour running mean | One 8-hour period in any 12-month period |
| Nitrogen dioxide | 200 μg m-3 | 1 hour mean | 9 hours in any 12-month period |
| PM10 | 50 μg m-3 | 24-hour mean | One 24-hour period in any 12-month period |
| Ozone | 150 μg m-3 | 1 hour mean | Not to be exceeded |
| Sulphur dioxide | 350 μg m-3 570 μg m-3 |
1 hour mean 1 hour mean |
9 hours in any 12-month period Not to be exceeded |
*Source: Resource Management (National Environmental Standards relating to certain air pollutants, dioxins and other toxins) Regulations 2004.
Indoor air quality
Indoor air quality is important as people spend most of their time indoors. Contributing factors to poor indoor air quality include cooking, home heating, smoking and inadequate ventilation. Common indoor air pollutants include NO2, CO, PM10, volatile organic compounds (VOCs), tobacco smoke, toxic moulds, water vapour, and various particulates such as asbestos and fine particulates (PM10 and PM2.5). Water vapour and NO2 are produced by unvented gas heaters and appliances (including stoves).
For information on additional potential indoor pollutants and sources see Table 2.
| Factors influencing indoor air quality | Potentially emitted pollutant |
|---|---|
| Building operation and activity | |
| Tobacco smoke | Fine particles, polycyclic aromatic hydrocarbons (PAHs) benzene |
| Human breath | Ethanol, methanol, and carbon dioxide |
| Chlorinated water supplies used in washing activities | Chloroform |
| Petrol or car exhaust vapour entering building from attached garages | Benzene, carbon monoxide, volatile organic compounds (VOCs) |
| Fuel-based heating and cooking appliances especially if unflued | Butane, carbon monoxide, limonene, n-hexane, propane, fine particles, acrolein, NOX, formaldehyde |
| Construction products (wet) | |
| Adhesives and sealants | Acetone, ethanol, formaldehyde, methanol, VOCs |
| Timber stains, paints, coatings | Ethanol, methanol, methyl chloroform, xylene, toluene, VOCs, lead |
| Polyurethane lacquer / floor varnish, including those used on concrete | Acetone, benzene, xylene, toluene, isobutyraldehyde |
| Construction products (dry) | |
| Plastic and rubber, flooring and carpet underlay | VOCs |
| Carpet | Dust mites, 4-vinylcyclohexane |
| Wallpapers | Mould inhibitors |
| Friable products | Asbestos, fibreglass |
| Insulation products | Formaldehyde |
| Building contents | |
| Furniture | Dust mites, VOCs, formaldehyde |
| Office equipment | Ozone, VOCs, respiratory suspended particles |
| Cupboards/shelving | Formaldehyde, nonanal |
| Dry cleaned clothing | Methyl chloroform, tetrachloroethylene |
| Printed material | Formaldehyde, nonanal, toluene |
| Household products | |
| Waxes and polishes | VOCs |
| Cleaners, disinfectants and detergents | Benzene, butane, ethanol, toluene, formaldehyde, limonene, methanol |
| Cosmetics | Ethanol, methanol, nonanal |
| Room deodorizers | p-Dichlorobenzene |
| Outdoor sources | |
| Soil and rocks in the building site | Radon |
| Infiltration from outdoor environment | Sulphur dioxide, ozone, fine particles, PAHs, benzene, carbon monoxide, NOX |
Unflued gas heaters produce NO2 and CO and pose a significant health risk to children, pregnant women, elderly people and those with asthma or heart disease. There is currently limited NZ data on indoor air quality; however, several NZ studies have shown that using unflued gas appliances can expose people to levels of nitrogen dioxide which exceed World Health Organization (WHO) guidelines.
Ventilation is the key factor to ensure a healthy indoor environment and may be achieved by natural or mechanical means. It is important that proper type of ventilation used indoor does not expose occupants to high levels of other health risk. Natural ventilation may not be appropriate if opening windows regularly exposes occupants to significant levels of noise or outdoor air pollution.
