#ID: ID_BEI_DC
 #City: Beijing
 #Station: Dongcheng
 #Name: 东城东四
 #Latitude: 39.929
 #Longitude: 116.417
 #Timezone: +0800
 Date,PM10,PM25,CO,Ozone,Sulphur Dioxide,Nitrogen Dioxide,AmbientTemperature,RelativeHumidity,WindDirection,WindSpeed,Pressure,RainGauge
 Unit,ug/m3,ug/m3,ppm,µg/m3,µg/m3,µg/m3,°C,%,°,m/s,hPa,mm
 10/29/2016 13:00,16,3,,58,10,3,32,66,200,3,1001,0
 10/29/2016 14:00,19,8,,57,9,4,32,64,197,2,1001,0
 10/29/2016 15:00,15,9,,52,47,17,30,72,190,2,1001,0
 10/29/2016 16:00,31,19,,52,34,17,30,75,191,2,1001,0
 10/29/2016 17:00,31,17,,49,49,19,29,75,194,1,1002,0
 10/29/2016 18:00,37,18,,45,55,25,29,73,183,1,1003,0
 10/29/2016 19:00,24,13,,40,21,19,29,80,65,1,1004,0
 10/29/2016 20:00,39,22,,44,4,16,28,85,7,1,1005,0
 10/29/2016 21:00,24,16,,43,3,7,28,85,10,1,1005,0
 

This is an example based on an HTML format (direct url: publishingdata/html/):

This is an example based on JSON format (direct url: /publishingdata/json/)

..

For instant particule counters, such as the Plantower PMS or Nova SDS, which provide instantaneous (in few seconds) particulate matter readings, the data is usually reported every minute. This data is usually computed based on several "averaged" readings from a one or two minute period.

The use of averaging is however not good enough, especially for failing sensors (or sensor close of end-of-life). Therefore, for such sensors, it is required to provide additional metrics, such as the median, min, max, and standard-deviation. See for example the readings object in the below JSON data feed.

..

You can use the following arduino-compatible code to collect those metrics:

class Accumulator 
{ 
    #define OUTPUT_BUFFER_SIZE 120 
    char buffer[OUTPUT_BUFFER_SIZE]; 
 
    #define MAXACCVALUES 120 
    int vals[MAXACCVALUES]; 
 
    int count = 0; 
 
public: 
    Accumulator() 
    { 
        reset(); 
    } 
 
    void reset() 
    { 
        count = 0; 
        for (int i=0;i< MAXACCVALUES;i++)  
        { 
            vals[i]=0; 
        } 
    } 
 
    bool hasData()  
    { 
        return count!=0; 
    } 
 
    std::string output()  
    { 
        if (!hasData()) return std::string("{}"); 
 
        sprintf(buffer, OUTPUT_BUFFER_SIZE, "{\"min\":%d,\"max\":%d,\"median\":%d,\"average\":%.1f,\"stddev\":%.1f,\"count\":%d}",  
            vmin(), vmax(), median(), average(), stddev(), count); 
 
        return std::string(buffer); 
 
    } 
 
    void add(int val) 
    { 
        if (count==MAXACCVALUES-1) { 
          for (int i = 0; i < MAXACCVALUES - 1; i++) { 
            vals[i] = vals[i + 1]; 
            } 
            count --; 
        } 
        vals[count++]=val; 
    } 
 
    float stddev()  
    { 
        if (!hasData()) return -1; 
        int u  =avg(); 
        int t = 0; 
        for (int i=0;ivals[j]) { 
                    float t = vals[j]; 
                    vals[j]=vals[i]; 
                    vals[i]=t; 
                } 
  
            } 
        } 
        return vals[count/2]; 
    } 
 
    float avg()  
    { 
        if (!hasData()) return -1; 
        float t = 0; 
        for (int i=0;ivals[i]) { 
                t=vals[i]; 
            } 
        } 
        return t; 
    } 
 
    float vmax()  
    { 
        if (!hasData()) return -1; 
        float t = vals[0]; 
        for (int i=0;it) { 
                t=vals[i]; 
            } 
        } 
        return t; 
    } 
};