Detection of toxic gases such as hydrogen sulfide (H₂S) at low temperatures is of high importance as it reduces power consumption, increases long-term stability, and lowers the danger of explosion in the presence of flammable gases. Among different gas sensors, chemiresistive metal oxide semi-conductor sensors are the most popular type due to their low cost, high sensitivity, compact size, ease of use, and high thermal and mechanical stability. However, these sensors generally require a high operating temperature (>100℃), attributed to their insufficient surface area. Hence, their pristine bulk structures cannot meet the requirements of low-temperature gas sensing. To overcome these limitations, the bulk structure of metal oxide sensors can be modified geometrically for an increased surface area. Herein, we fabricated flower-like ZnO nanorods using a modified hydrothermal method in two different grain sizes of 19 and 23nm. The sample was tested toward H₂S and a range of volatile organic compounds. The sample with smaller grain size provided 7.4 as response value as well as fast response and recovery time of 293 and 186s, respectively, toward 100ppm H2S at room temperature. The results indicate the potential of the sensing layer for real-time monitoring and detection of hazardous gases detection at room temperature.