The recent research advancements in the field of chemical sensors, distributed sensing and wireless networking have led to development of several low-cost optical aerosol sensors. These sensors are based on the principle of particle light scattering, and are dependent on several parameters - temperature, relative humidity, particle size, and particle concentration. However, the linearity of the response of these sensors over a wide concentration range has not been well studied. We evaluated a low-cost particulate matter measuring sensor (BlueSky Air Monitor Model 8143 TSI Inc) in different environments. The particulate matter concentration of PM10, PM4, PM2.5 and PM1 were compared with reference measurements using a Dust Trak Model 8534 TSI Inc- a widely used light scattering instrument. Several methodologies were developed to generate wide concentration of aerosols. The concentration ranges for the lower end were created in indoor environmental conditions (0.003-0.004 mg/m3) and for the higher end were created in a chamber with e-cigarette vaping (0.006- 30 mg/m3). The intermediate concentrations (0.003- 2 mg/m3) were obtained using a Concentrated Air Particulate System (CAPS) consisting of a virtual impactor setup that magnifies ambient concentration by an adjustable enrichment factor between 5-20. Results of the present study indicate that the BlueSky low cost sensor compares well with the reference instrument (R2 = 0.92; Intercept ~0; Slope = 0.75). The novel design of the CAPS including maintaining an uniform temperature and humidity makes it an ideal design for characterizing low cost sensors over a wide range of concentrations. The findings of the present study can be used to design more robust methodologies for laboratory testing for low cost air quality sensors at different concentrations.