世衛研究：PM2.5導致不良生育結果、早死

Long-term exposure to fine particles of pollutants in the air can trigger adverse birth outcomes, childhood respiratory diseases and atherosclerosis, the World Health Organization warned today.

The report on particles smaller than 2.5 micrometers, or PM2.5, also suggests a link with neurodevelopment, cognitive function and diabetes, and strengthens the causal link between PM2.5 and cardiovascular and respiratory deaths.

Particulate matter consists of a mixture of solid and liquid particles suspended in the air a mix of sulphates, nitrates, ammonium, and other substances. The main sources of man-made PM include heating in households, industrial activities and road traffic.

More than 80 percent of Europeans are exposed to particulate matter levels above the 2005 WHO Air Quality Guidelines, depriving each person of 8.6 months of life, says the health agency.

The WHO review recommends a revision of the Air Quality Guidelines for particulate matter by 2015, establishing a stricter guideline for nitrogen dioxide (NO2), and the development of a guideline for long-term average ozone concentrations.

The study, "Review of evidence on health aspects of air pollution" was conducted at the request of the European Commission in the framework of the 2013 review of the European Union's air policy.

EU Commissioner for Environment Janez Potočnik said, "EU air policy must be based on the latest science. That is why I asked the WHO to undertake this research. The links it has found between air pollution and human health reinforce the case for scaling up our policy. It will be a key input to the 2013 air quality policy review."

Commissioner Potočnik has declared 2013 as the Year of Air for EU policies. The plan is to highlight the importance of clean air for all and to focus on actions to improve air quality across the EU.

"Only a few years ago in the absence of clear evidence, air pollution standards and regulations were not sufficiently targeting human health," said Zsuzsanna Jakab, WHO Regional Director for Europe. "Years of WHO-coordinated research have provided the first quantitative estimates of the burden of disease from particulate matter and have now established links between air pollutants and health outcomes."

"We are confident that this new knowledge will ultimately lead to more stringent air pollution control policies to protect the health of European citizens," she said.

WHO also recommends modifications to EU law, because the current limit value for PM2.5 in the EU's Ambient Air Quality Directive is twice as high as WHO's Air Quality Guidelines recommend.

Health effects of particulate matter in the air have long been known to include respiratory and cardiovascular diseases and lung cancer.

The WHO review found new evidence for effects of long-term exposures to ground-level ozone on respiratory mortality and on deaths among persons with predisposing chronic conditions.

Ozone exposure also impacts cognitive development and reproductive health, including preterm birth, the WHO study found.

This adds to previous findings on short-term effects which are the focus of current regulation.

The review recommends the development of an Air Quality Directive for long-term average ozone concentrations.

A new guideline is recommended for NO2, a toxic gas produced by the combustion process in heating, power generation and especially vehicle engines.

New studies have associated short-term and long-term exposure to NO2 with mortality, hospital admissions, and respiratory symptoms at concentrations at or below the current EU limit values, which are set at the same level as the WHO guidelines.

The 2005 WHO Air quality guidelines are designed to offer global guidance on reducing the health impacts of air pollution.

While the original guidelines had a European scope, the latest 2005 guidelines apply worldwide and are based on expert evaluation of current scientific evidence. They recommend limits for the concentration of particulate matter, ground-level ozone, nitrogen dioxide and sulfur dioxide.