Module: PM25

Defined in:
lib/pm_25.rb,
lib/pm_25/version.rb

Constant Summary collapse

API_base =

Yes, pm25.in requires a token but uses http!

'http://www.pm25.in/api/querys/'
VERSION = 
"0.0.2"

Class Method Summary collapse

Class Method Details

.access_api(interface, params = {}) ⇒ Hash, Fixnum

TODO pm25.in tends to 502, need to email complaints and handle this.

Parameters:

  • interface (String) —

    of api

  • params (Hash) (defaults to: {}) —

    (additional) options

Returns:

  • (Hash) —

    result

  • (Fixnum) —

    error code



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# File 'lib/pm_25.rb', line 59

def access_api(interface, params={})
  params[:token] ||= get_token
  res = RestClient.get(API_base + interface, {params: params})
  if res.code == 200
    JSON.parse res.body
  else
    res.code
  end
end

.all_cities(token = nil) ⇒ Hash, Fixnum

Get PM 2.5 data for all cities. API frequency limit: 5 per hour.

Parameters:

  • token (String) (defaults to: nil)

Returns:

  • (Hash)
  • (Fixnum) —

    error code



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# File 'lib/pm_25.rb', line 157

def all_cities(token=nil)
  access_api('all_cities.json', token: token)
end

.aqi_ranking(token = nil) ⇒ Hash, Fixnum

Get average data for all cities. (Cities are sorted by AQI.) API frequency limit: 15 per hour.

Parameters:

  • token (String) (defaults to: nil)

Returns:

  • (Hash)
  • (Fixnum) —

    error code



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# File 'lib/pm_25.rb', line 166

def aqi_ranking(token=nil)
  access_api('aqi_ranking.json', token: token)
end

.available_cities(token = get_token) ⇒ Array, Fixnum

Get a list of cites providing PM 2.5 data. API frequency limit: 10 per hour.

Parameters:

  • token (String) (defaults to: get_token)

Returns:

  • (Array) —

    city list

  • (Fixnum) —

    error code



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# File 'lib/pm_25.rb', line 143

def available_cities(token=get_token)
  res = RestClient.get 'http://www.pm25.in/api/querys.json', {params: {token: token}}
  if res.code == 200
    JSON.parse(res.body)['cities']
  else
    res.code
  end
end

.bing_pm25(city) ⇒ Fixnum

Get PM 2.5 from bing.com

Parameters:

  • city (String) —

    only accept Chinese

Returns:

  • (Fixnum) —

    PM 25 value



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# File 'lib/pm_25.rb', line 174

def bing_pm25(city)
  city = URI.encode(city)
  bing_url = "http://cn.bing.com/search?q=#{city}+pm2.5"
  html = Nokogiri.parse(open(bing_url).read)
  html.at('#msn_pm25rt .b_xlText').content.to_i
end

.get_config(constant_name, default_value = nil) ⇒ String

Use environment variable or the value from config at the current directory. If all failed, use the default value.

Parameters:

  • constant_name (String)
  • default_value (String) (defaults to: nil)

Returns:

  • (String) 


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# File 'lib/pm_25.rb', line 22

def get_config(constant_name, default_value=nil)
  if ENV[constant_name]
    ENV[constant_name]
  elsif File.exist?('config.json')
    open('config.json') do |f|
      JSON.parse(f.read)[constant_name]
    end
  else
    default_value
  end
end

.get_default_city ⇒ String

Use environment variable PM25_IN_CITY or the value from config at the current directory.

Returns:

  • (String) —

    city



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# File 'lib/pm_25.rb', line 50

def get_default_city
  get_config('PM25_IN_CITY')
end

.get_token ⇒ String

Use environment variable PM25_IN_TOKEN or the value from config at the current directory. If all failed, use the test token. You can apply a token at pm25.in: www.pm25.in/api_doc

Returns:

  • (String) —

    token



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# File 'lib/pm_25.rb', line 41

def get_token
  test_token= '5j1znBVAsnSf5xQyNQyq'
  get_config('PM25_IN_TOKEN', test_token)
end

.just_pm25(city = get_default_city, token = nil) ⇒ Fixnum

Get PM 2.5 value for city. Fallback to bing.com. Return PM 2.5 value only.

Parameters:

  • city (String) (defaults to: get_default_city) —

    only accept Chinese

  • token (String) (defaults to: nil)

Returns:

  • (Fixnum) —

    average PM 2.5 value for stations



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# File 'lib/pm_25.rb', line 187

def just_pm25(city=get_default_city, token=nil)
  result = pm25(city, token)
  # error on pm25.in api
  if result.is_a? Fixnum
    bing_pm25(city)
  elsif result.include? 'error'
    bing_pm25(city)
  else
    publish_time = Time.parse(result[-1]['time_point'])
    # Data on pm25.in is too old.
    # According to GB 3095-2013, PM 2.5 should have hourly
    # average values for at least 20 hours a day.
    # http://hbj.shanghang.gov.cn/hjjc/gldt/201411/P020141110361645902554.pdf
    if Time.now - publish_time > 2.hours
      bing_pm25(city)
    else
      result[-1]['pm2_5']
    end
  end
end

.pm25(city = get_default_city, token = nil) ⇒ Array<Hash>

Get PM 2.5 info of all stations in the specified city. API frequency limit: 500 per hour.

  • Chinese (e.g. 广州)

  • area code (e.g. 020)

  • Pinyin (e.g. guangzhou)

If there is ambiguity in Pinyin, use ‘shi` as postfix, for example: 泰州 is taizhoushi, and 台州 is taizhou. For more information, see www.pm25.in/ Every station includes:

  • aqi (according to CN standard)

  • area

  • pm2_5

  • pm2_5_24h (moving average)

  • position_name (station name)

  • primary_pollutant

  • quality (优、良、轻度污染、中度污染、重度污染、严重污染 according to CN standard)

  • station_code

  • time_point (publish time of air condition)

Example:

pm25('zhuhai')

[

{
    "aqi"=> 82,
    "area"=> "珠海",
    "pm2_5"=> 31,
    "pm2_5_24h"=> 60,
    "position_name"=> "吉大",
    "primary_pollutant"=> "颗粒物(PM2.5)",
    "quality"=> "良",
    "station_code"=> "1367A",
    "time_point"=> "2013-03-07T19:00:00Z"
},
...
...
...
{
    "aqi"=> 108,
    "area"=> "珠海",
    "pm2_5"=> 0,
    "pm2_5_24h"=> 53,
    "position_name"=> "斗门",
    "primary_pollutant"=> "臭氧8小时",
    "quality"=> "轻度污染",
    "station_code"=> "1370A",
    "time_point"=> "2013-03-07T19:00:00Z"
},
{
    "aqi"=> 99,
    "area"=> "珠海",
    "pm2_5"=> 39,
    "pm2_5_24h"=> 67,
    "position_name"=> null,
    "primary_pollutant"=> null,
    "quality"=> "良",
    "station_code"=> null,
    "time_point"=> "2013-03-07T19:00:00Z"
}

]

Parameters:

  • city (String) (defaults to: get_default_city) —

    You can use

Returns:

  • (Array<Hash>) —

    an array of all stations



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# File 'lib/pm_25.rb', line 134

def pm25(city=get_default_city, token=nil)
  access_api('pm2_5.json', city: city, token: token)
end

.pm25_level(pm25) ⇒ Hash{Symbol: Fixnum, Symbol: String, Symbol: String, Symbol: String}

Get AQI category, meaning and action according to US standard.

Parameters:

  • (Fixnum)

Returns:

  • (Hash{Symbol: Fixnum, Symbol: String, Symbol: String, Symbol: String}) 


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# File 'lib/pm_25.rb', line 212

def pm25_level(pm25)
  if pm25 <= 12
    aqi_category = 'Good'
    aqi_meaning = 'Air quality is considered satisfactory, and air pollution poses little or no risk.'
    aqi_action = 'None'
  elsif pm25 <= 35.4
    aqi_category = 'Moderate'
    aqi_meaning = '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.'
    aqi_action = 'Unusually sensitive people should consider reducing prolonged or heavy exertion.'
  elsif pm25 <= 55.4
    aqi_category = 'Unhealthy for sensitive Groups'
    aqi_meaning = 'Members of sensitive groups may experience health effects. The general public is not likely to be affected.'
    aqi_action = 'People with heart or lung disease, children and older adults should reduc e prolonged or heavy exertion'
  elsif pm25 <= 150.4
    aqi_category = 'Unhealthy'
    aqi_meaning = 'Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects.'
    aqi_action = 'People with heart or lung disease, children and older adults should avoid prolonged or heavy exertion. Everyone else should reduce prolonged or heavy exertion.'
  elsif pm25 <= 250.4
    aqi_category = 'Very Unhealthy'
    aqi_meaning = 'Health warnings of emergency conditions. The entire population is more likely to be affected.'
    aqi_action = 'People with heart or lung disease, children and older adults should avoid all physical activity outdoors. Everyone else should avoid prolonged or heavy exertion.'
  else
    aqi_category = 'Hazardous'
    aqi_meaning = 'Health alert: everyone may experience more serious health effects'
    aqi_action = 'Avoid all physical activity outdoors.'
  end
{pm25: pm25,
 category: aqi_category,
 meaning: aqi_meaning,
 action: aqi_action}
end