原文连接：http://sunote.info/tag/beijingair/
从2月9日开始，@BeijingAir修改了报告的内容，从原来的报告过去1小时和当天平均值改为PM2.5和Ozone两个值。
原来的格式为：
2-9-2010 ; 11:00 ; Latest Hour ; 0.091 ; 169 ; Unhealthy ; Today’s Avg ; 0.216 ; 266 ; Very Unhealthy
现在的格式为：
02-21-2010; 09:00; PM2.5; 189.0; 239; Very Unhealthy // Ozone; 0.9; 1; Good
@BeijingAir是美驻华使馆在使馆区设置的一个空气检测站，将数据每隔一小时自动发送到twitter上。以前的数值仅仅为PM2.5，2月9日之后增加了Ozone。
几种污染物
PM2.5是Particulate matter 2.5的缩写，指大气中直径小于或等于2.5微米的颗粒物，也称为可入肺颗粒物。会进入肺部的气体交换区（肺泡），引起血管炎和动脉粥样硬化，进而导致心脏病和其他循环系统疾病。
PM10指直径等于或小于10微米，可以进入人的呼吸系统的颗粒物，也称为可吸入颗粒物。10微米到2.5微米的颗粒，部分会被肺呼出，部分被支气管和肺部组织吸附。
PM100指直径小于和等于100微米的颗粒物，也称总悬浮颗粒物。大于10微米的大多数被鼻腔和咽喉阻挡，不会造成麻烦。
PM2.5的影响
大气中PM-2.5污染控制的意义与途径一文中提到：
- PM-2.5是导致城市人为能见度下降的祸首
- PM-2.5是城市大气污染物中损害人体健康的元凶
什么是Ozone
Ozone是我们呼吸的空气，对人体健康有直接地影响。
解读@BeijingAir数据
目前@BeijingAir的数据格式为：
日期; 时间; PM2.5; PM2.5浓度; PM2.5空气质量指数; 健康等级 // Ozone; Ozone浓度; Ozone指数; Ozone健康等级
PM2.5的空气质量指数
Air Quality Index
Levels of Health Concern |
Numerical
Value |
Meaning |
| Good |
0 to 50 |
Air quality is considered satisfactory, and air pollution poses little or no risk |
| Moderate |
51 to 100 |
Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution. |
| Unhealthy for Sensitive Groups |
101 to 150 |
Members of sensitive groups may experience health effects. The general public is not likely to be affected. |
|
|
151 to 200 |
Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects. |
| Very Unhealthy |
201 to 300 |
Health alert: everyone may experience more serious health effects |
| Hazardous |
301 to 500 |
Health warnings of emergency conditions. The entire population is more likely to be affected. |
(来源)
Ozone指数
| Air Quality Index |
Protect Your Health |
Good
(0-50) |
No health impacts are expected when air quality is in this range. |
Moderate
(51-100) |
Unusually sensitive people should consider limiting prolonged outdoor exertion. |
Unhealthy for Sensitive Groups
(101-150) |
The following groups should limit prolonged outdoor exertion:
- People with lung disease, such as asthma
- Children and older adults
- People who are active outdoors
|
Unhealthy
(151-200) |
The following groups should avoid prolonged outdoor exertion:
- People with lung disease, such as asthma
- Children and older adults
- People who are active outdoors
Everyone else should limit prolonged outdoor exertion. |
Very Unhealthy
(201-300) |
The following groups should avoid all outdoor exertion:
- People with lung disease, such as asthma
- Children and older adults
- People who are active outdoors
Everyone else should limit outdoor exertion. |
(来源)